Since the advent of water cooled internal combustion engines, it has been an ongoing quest to improve air flow capabilities of the cooling systems, and thereby, increase overall cooling system performance. In a conventional cooling system, a single axial flow fan pushes air through the heat exchanger. In highly loaded systems, air velocity is typically greatest at the tips of the fans blades, and therefore, air flow is greatest through that corresponding area of the heat exchanger, generally at the heat exchanger's perimeter. In comparison, air velocity is typically lowest near the center of the fan, and therefore, air flow is lowest through that corresponding area of the heat exchanger, generally at the central portion of the heat exchanger. Air flow through the heat exchanger may even be substantially zero at the area corresponding to the exact center of the fan. Another disadvantage of the conventional system is the air already pushed through the greater air flow area may be recirculated back through the heat exchanger via the lesser air flow area. These conditions reduce the overall performance of the cooling system compared to the performance that would exist if the air velocities were uniform across the face of the heat exchanger.
The cooling systems for some internal combustion engines have incorporated dual fans in order to improve overall performance and air flow capabilities of current conventional single fan cooling system designs while also allowing various heat exchanger shapes. The dual fans are arbitrarily mounted to push or pull air through the heat exchangers. One of the problems encountered therewith is that the arbitrary mounting of the dual fans may not position the fans at the necessary locations to produce the most effective air flow through the heat exchanger.
Other known cooling systems have a first fan to push or pull air through the heat exchanger and a second fan to push or pull air through a separate area of a vehicle such as through a separate engine compartment. Since the second fan evacuates the hot air within the engine compartment, the hot air does not pass through the cooling system, thus improving performance. However, using two fans in this manner does not improve the air flow capabilities through the heat exchanger although cooling system performance may be increased due to the cooler air passing through the heat exchanger.
The present invention is directed to overcoming one or more of the problems as set forth above.